The present invention relates to a power window apparatus for a vehicle, and more particularly to a power window apparatus which is capable of preventing a foreign matter from being excessively sandwiched between a window glass and a window flame.
Power window apparatuses have been widely used in automotive vehicles to facilitate driver""s operations for opening and closing window glasses of a vehicle. A typical power window apparatus is capable of executing a manual operation for opening and closing a window glass for a period during which an opening/closing operation switch is set at on-state, an automatic operation for opening the window glass to a full open state and closing the window glass to a full close state, and a sandwich preventing function for preventing a foreign matter from being sandwiched between a window glass and a window frame. Since two-contact type operation switch is widely used in such a power window apparatus to lower the cost of production, a switching between the manual operation and the automatic operation is executed on the basis of a time period during which the operation switch is being turned on.
However, such a power window apparatus employing a two-contact type operation switch has a problem that it is difficult, due to an operational limitation of the two-contact type operation switch, to smoothly execute both of a positional justification of a window glass and an accurate detection of a foreign matter sandwiched between the window glass and a window frame.
It is therefore an object of the present invention to provide an improved power window apparatus which is capable of smoothly executing both of a positional justification of a window glass and an accurate detection of a foreign matter so as to enable a window closing operation even under a large-frictional condition of the window glass.
An aspect of the present invention resides in a power window apparatus for a vehicle which comprises: a drive motor for raising and lowering a window glass; an operation switch comprising a raising contact which outputs a window raising command when the raising contact is set at on-state and a lowering contact which outputs a window lowering command when the lowering contact is set at on-state; and a controller coupled to the drive motor and the operation switch. The controller is arranged to execute a manual operation during a time period from a start moment at which the operation switch starts outputting one of the window raising and lowering commands to a first moment at which a first predetermined time period elapses from the start moment, to execute an automatic operation during a time period from the first moment to a second moment at which a second predetermined time period elapses from the start moment, and to execute the manual operation from the second moment.
Another aspect of the present invention resides in a method of controlling a drive motor for raising and lowering a window glass which comprises a step for executing a manual operation during a time period from a start moment at which an operation switch outputs one of a window raising and lowering commands to a first moment at which a first predetermined time period has elapsed from the start moment; a step executing an automatic operation during a time period from the first moment to a second moment at which a second predetermined time period has elapsed from the start moment, and a step for executing the manual operation from the second moment.
A further another aspect of the present invention resides in a power window apparatus for a vehicle, comprising: a drive motor for raising and lowering a window glass; an operation switch outputting a window closing command when a vehicle occupant turns on the operation switch; a rotation detector attached to the drive motor and detecting a rotation speed of the drive motor; and a controller coupled to the drive motor, the operation switch and the rotation detector. The controller is arranged to operate the drive motor so as to raise the window glass from a start moment at which the operation switch outputs the window raising command, to count an elapsed time from the start moment, to calculate a load applied to the drive motor on the basis of the rotation speed of the drive motor, to stop operating the drive motor when the load is greater than a predetermined load, to operate the drive motor so as to lower the window glass when the operation switch stops outputting the window raising command before the elapsed time reaches a predetermined time period and when the load is greater than the predetermined load, to restart the operation of the drive motor to raise the window glass from a moment at which the elapsed time reaches the predetermined time period and when the operation switch continues outputting the window raising signal.
The other objects and features of this invention will become understood from the following description with reference to the accompanying drawings.